Representational state transfer (REST) is an abstraction of the architecture of the World Wide Web. More precisely, REST is an architectural style including a coordinated set of architectural constraints applied to components, connectors, and data elements within a distributed hypermedia system. REST ignores the details of component implementation and protocol syntax in order to focus on the roles of components, the constraints upon their interaction with other components, and their interpretation of significant data elements.
The REST architectural style may be applied to the development of web services as an alternative to other distributed-computing specifications such as, for example, Simple Object Access protocol (SOAP). One can characterize web services as “RESTful” if they conform to certain architectural constraints involving or relating to a client-server model, a stateless protocol, a web cache, a layered system, code on demand (optional), and a uniform interface.
In some circumstances, the REST architectural style may be applied to web application programming interfaces (APIs). Web APIs that adhere to the architectural constraints are called RESTful.